Committer: Michael Beasley <mike@snafu.setup>

[mikesnafu-overlay.git] / drivers / ata / pata_pdc2027x.c

/*
 *  Promise PATA TX2/TX4/TX2000/133 IDE driver for pdc20268 to pdc20277.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 *  Ported to libata by:
 *  Albert Lee <albertcc@tw.ibm.com> IBM Corporation
 *
 *  Copyright (C) 1998-2002             Andre Hedrick <andre@linux-ide.org>
 *  Portions Copyright (C) 1999 Promise Technology, Inc.
 *
 *  Author: Frank Tiernan (frankt@promise.com)
 *  Released under terms of General Public License
 *
 *
 *  libata documentation is available via 'make {ps|pdf}docs',
 *  as Documentation/DocBook/libata.*
 *
 *  Hardware information only available under NDA.
 *
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_cmnd.h>
#include <linux/libata.h>

#define DRV_NAME        "pata_pdc2027x"
#define DRV_VERSION     "1.0"
#undef PDC_DEBUG

#ifdef PDC_DEBUG
#define PDPRINTK(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ## args)
#else
#define PDPRINTK(fmt, args...)
#endif

enum {
        PDC_MMIO_BAR            = 5,

        PDC_UDMA_100            = 0,
        PDC_UDMA_133            = 1,

        PDC_100_MHZ             = 100000000,
        PDC_133_MHZ             = 133333333,

        PDC_SYS_CTL             = 0x1100,
        PDC_ATA_CTL             = 0x1104,
        PDC_GLOBAL_CTL          = 0x1108,
        PDC_CTCR0               = 0x110C,
        PDC_CTCR1               = 0x1110,
        PDC_BYTE_COUNT          = 0x1120,
        PDC_PLL_CTL             = 0x1202,
};

static int pdc2027x_init_one(struct pci_dev *pdev, const struct pci_device_id *ent);
static void pdc2027x_error_handler(struct ata_port *ap);
static void pdc2027x_set_piomode(struct ata_port *ap, struct ata_device *adev);
static void pdc2027x_set_dmamode(struct ata_port *ap, struct ata_device *adev);
static int pdc2027x_check_atapi_dma(struct ata_queued_cmd *qc);
static unsigned long pdc2027x_mode_filter(struct ata_device *adev, unsigned long mask);
static int pdc2027x_cable_detect(struct ata_port *ap);
static int pdc2027x_set_mode(struct ata_link *link, struct ata_device **r_failed);

/*
 * ATA Timing Tables based on 133MHz controller clock.
 * These tables are only used when the controller is in 133MHz clock.
 * If the controller is in 100MHz clock, the ASIC hardware will
 * set the timing registers automatically when "set feature" command
 * is issued to the device. However, if the controller clock is 133MHz,
 * the following tables must be used.
 */
static struct pdc2027x_pio_timing {
        u8 value0, value1, value2;
} pdc2027x_pio_timing_tbl [] = {
        { 0xfb, 0x2b, 0xac }, /* PIO mode 0 */
        { 0x46, 0x29, 0xa4 }, /* PIO mode 1 */
        { 0x23, 0x26, 0x64 }, /* PIO mode 2 */
        { 0x27, 0x0d, 0x35 }, /* PIO mode 3, IORDY on, Prefetch off */
        { 0x23, 0x09, 0x25 }, /* PIO mode 4, IORDY on, Prefetch off */
};

static struct pdc2027x_mdma_timing {
        u8 value0, value1;
} pdc2027x_mdma_timing_tbl [] = {
        { 0xdf, 0x5f }, /* MDMA mode 0 */
        { 0x6b, 0x27 }, /* MDMA mode 1 */
        { 0x69, 0x25 }, /* MDMA mode 2 */
};

static struct pdc2027x_udma_timing {
        u8 value0, value1, value2;
} pdc2027x_udma_timing_tbl [] = {
        { 0x4a, 0x0f, 0xd5 }, /* UDMA mode 0 */
        { 0x3a, 0x0a, 0xd0 }, /* UDMA mode 1 */
        { 0x2a, 0x07, 0xcd }, /* UDMA mode 2 */
        { 0x1a, 0x05, 0xcd }, /* UDMA mode 3 */
        { 0x1a, 0x03, 0xcd }, /* UDMA mode 4 */
        { 0x1a, 0x02, 0xcb }, /* UDMA mode 5 */
        { 0x1a, 0x01, 0xcb }, /* UDMA mode 6 */
};

static const struct pci_device_id pdc2027x_pci_tbl[] = {
        { PCI_VDEVICE(PROMISE, PCI_DEVICE_ID_PROMISE_20268), PDC_UDMA_100 },
        { PCI_VDEVICE(PROMISE, PCI_DEVICE_ID_PROMISE_20269), PDC_UDMA_133 },
        { PCI_VDEVICE(PROMISE, PCI_DEVICE_ID_PROMISE_20270), PDC_UDMA_100 },
        { PCI_VDEVICE(PROMISE, PCI_DEVICE_ID_PROMISE_20271), PDC_UDMA_133 },
        { PCI_VDEVICE(PROMISE, PCI_DEVICE_ID_PROMISE_20275), PDC_UDMA_133 },
        { PCI_VDEVICE(PROMISE, PCI_DEVICE_ID_PROMISE_20276), PDC_UDMA_133 },
        { PCI_VDEVICE(PROMISE, PCI_DEVICE_ID_PROMISE_20277), PDC_UDMA_133 },

        { }     /* terminate list */
};

static struct pci_driver pdc2027x_pci_driver = {
        .name                   = DRV_NAME,
        .id_table               = pdc2027x_pci_tbl,
        .probe                  = pdc2027x_init_one,
        .remove                 = ata_pci_remove_one,
};

static struct scsi_host_template pdc2027x_sht = {
        .module                 = THIS_MODULE,
        .name                   = DRV_NAME,
        .ioctl                  = ata_scsi_ioctl,
        .queuecommand           = ata_scsi_queuecmd,
        .can_queue              = ATA_DEF_QUEUE,
        .this_id                = ATA_SHT_THIS_ID,
        .sg_tablesize           = LIBATA_MAX_PRD,
        .cmd_per_lun            = ATA_SHT_CMD_PER_LUN,
        .emulated               = ATA_SHT_EMULATED,
        .use_clustering         = ATA_SHT_USE_CLUSTERING,
        .proc_name              = DRV_NAME,
        .dma_boundary           = ATA_DMA_BOUNDARY,
        .slave_configure        = ata_scsi_slave_config,
        .slave_destroy          = ata_scsi_slave_destroy,
        .bios_param             = ata_std_bios_param,
};

static struct ata_port_operations pdc2027x_pata100_ops = {
        .mode_filter            = ata_pci_default_filter,

        .tf_load                = ata_tf_load,
        .tf_read                = ata_tf_read,
        .check_status           = ata_check_status,
        .exec_command           = ata_exec_command,
        .dev_select             = ata_std_dev_select,

        .check_atapi_dma        = pdc2027x_check_atapi_dma,
        .bmdma_setup            = ata_bmdma_setup,
        .bmdma_start            = ata_bmdma_start,
        .bmdma_stop             = ata_bmdma_stop,
        .bmdma_status           = ata_bmdma_status,
        .qc_prep                = ata_qc_prep,
        .qc_issue               = ata_qc_issue_prot,
        .data_xfer              = ata_data_xfer,

        .freeze                 = ata_bmdma_freeze,
        .thaw                   = ata_bmdma_thaw,
        .error_handler          = pdc2027x_error_handler,
        .post_internal_cmd      = ata_bmdma_post_internal_cmd,
        .cable_detect           = pdc2027x_cable_detect,

        .irq_clear              = ata_bmdma_irq_clear,
        .irq_on                 = ata_irq_on,

        .port_start             = ata_sff_port_start,
};

static struct ata_port_operations pdc2027x_pata133_ops = {
        .set_piomode            = pdc2027x_set_piomode,
        .set_dmamode            = pdc2027x_set_dmamode,
        .set_mode               = pdc2027x_set_mode,
        .mode_filter            = pdc2027x_mode_filter,

        .tf_load                = ata_tf_load,
        .tf_read                = ata_tf_read,
        .check_status           = ata_check_status,
        .exec_command           = ata_exec_command,
        .dev_select             = ata_std_dev_select,

        .check_atapi_dma        = pdc2027x_check_atapi_dma,
        .bmdma_setup            = ata_bmdma_setup,
        .bmdma_start            = ata_bmdma_start,
        .bmdma_stop             = ata_bmdma_stop,
        .bmdma_status           = ata_bmdma_status,
        .qc_prep                = ata_qc_prep,
        .qc_issue               = ata_qc_issue_prot,
        .data_xfer              = ata_data_xfer,

        .freeze                 = ata_bmdma_freeze,
        .thaw                   = ata_bmdma_thaw,
        .error_handler          = pdc2027x_error_handler,
        .post_internal_cmd      = ata_bmdma_post_internal_cmd,
        .cable_detect           = pdc2027x_cable_detect,

        .irq_clear              = ata_bmdma_irq_clear,
        .irq_on                 = ata_irq_on,

        .port_start             = ata_sff_port_start,
};

static struct ata_port_info pdc2027x_port_info[] = {
        /* PDC_UDMA_100 */
        {
                .flags          = ATA_FLAG_NO_LEGACY | ATA_FLAG_SLAVE_POSS |
                                  ATA_FLAG_MMIO,
                .pio_mask       = 0x1f, /* pio0-4 */
                .mwdma_mask     = 0x07, /* mwdma0-2 */
                .udma_mask      = ATA_UDMA5, /* udma0-5 */
                .port_ops       = &pdc2027x_pata100_ops,
        },
        /* PDC_UDMA_133 */
        {
                .flags          = ATA_FLAG_NO_LEGACY | ATA_FLAG_SLAVE_POSS |
                                  ATA_FLAG_MMIO,
                .pio_mask       = 0x1f, /* pio0-4 */
                .mwdma_mask     = 0x07, /* mwdma0-2 */
                .udma_mask      = ATA_UDMA6, /* udma0-6 */
                .port_ops       = &pdc2027x_pata133_ops,
        },
};

MODULE_AUTHOR("Andre Hedrick, Frank Tiernan, Albert Lee");
MODULE_DESCRIPTION("libata driver module for Promise PDC20268 to PDC20277");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
MODULE_DEVICE_TABLE(pci, pdc2027x_pci_tbl);

/**
 *      port_mmio - Get the MMIO address of PDC2027x extended registers
 *      @ap: Port
 *      @offset: offset from mmio base
 */
static inline void __iomem *port_mmio(struct ata_port *ap, unsigned int offset)
{
        return ap->host->iomap[PDC_MMIO_BAR] + ap->port_no * 0x100 + offset;
}

/**
 *      dev_mmio - Get the MMIO address of PDC2027x extended registers
 *      @ap: Port
 *      @adev: device
 *      @offset: offset from mmio base
 */
static inline void __iomem *dev_mmio(struct ata_port *ap, struct ata_device *adev, unsigned int offset)
{
        u8 adj = (adev->devno) ? 0x08 : 0x00;
        return port_mmio(ap, offset) + adj;
}

/**
 *      pdc2027x_pata_cable_detect - Probe host controller cable detect info
 *      @ap: Port for which cable detect info is desired
 *
 *      Read 80c cable indicator from Promise extended register.
 *      This register is latched when the system is reset.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */
static int pdc2027x_cable_detect(struct ata_port *ap)
{
        u32 cgcr;

        /* check cable detect results */
        cgcr = ioread32(port_mmio(ap, PDC_GLOBAL_CTL));
        if (cgcr & (1 << 26))
                goto cbl40;

        PDPRINTK("No cable or 80-conductor cable on port %d\n", ap->port_no);

        return ATA_CBL_PATA80;
cbl40:
        printk(KERN_INFO DRV_NAME ": 40-conductor cable detected on port %d\n", ap->port_no);
        return ATA_CBL_PATA40;
}

/**
 * pdc2027x_port_enabled - Check PDC ATA control register to see whether the port is enabled.
 * @ap: Port to check
 */
static inline int pdc2027x_port_enabled(struct ata_port *ap)
{
        return ioread8(port_mmio(ap, PDC_ATA_CTL)) & 0x02;
}

/**
 *      pdc2027x_prereset - prereset for PATA host controller
 *      @link: Target link
 *      @deadline: deadline jiffies for the operation
 *
 *      Probeinit including cable detection.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static int pdc2027x_prereset(struct ata_link *link, unsigned long deadline)
{
        /* Check whether port enabled */
        if (!pdc2027x_port_enabled(link->ap))
                return -ENOENT;
        return ata_std_prereset(link, deadline);
}

/**
 *      pdc2027x_error_handler - Perform reset on PATA port and classify
 *      @ap: Port to reset
 *
 *      Reset PATA phy and classify attached devices.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static void pdc2027x_error_handler(struct ata_port *ap)
{
        ata_bmdma_drive_eh(ap, pdc2027x_prereset, ata_std_softreset, NULL, ata_std_postreset);
}

/**
 *      pdc2720x_mode_filter    -       mode selection filter
 *      @adev: ATA device
 *      @mask: list of modes proposed
 *
 *      Block UDMA on devices that cause trouble with this controller.
 */

static unsigned long pdc2027x_mode_filter(struct ata_device *adev, unsigned long mask)
{
        unsigned char model_num[ATA_ID_PROD_LEN + 1];
        struct ata_device *pair = ata_dev_pair(adev);

        if (adev->class != ATA_DEV_ATA || adev->devno == 0 || pair == NULL)
                return ata_pci_default_filter(adev, mask);

        /* Check for slave of a Maxtor at UDMA6 */
        ata_id_c_string(pair->id, model_num, ATA_ID_PROD,
                          ATA_ID_PROD_LEN + 1);
        /* If the master is a maxtor in UDMA6 then the slave should not use UDMA 6 */
        if (strstr(model_num, "Maxtor") == NULL && pair->dma_mode == XFER_UDMA_6)
                mask &= ~ (1 << (6 + ATA_SHIFT_UDMA));

        return ata_pci_default_filter(adev, mask);
}

/**
 *      pdc2027x_set_piomode - Initialize host controller PATA PIO timings
 *      @ap: Port to configure
 *      @adev: um
 *      @pio: PIO mode, 0 - 4
 *
 *      Set PIO mode for device.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */

static void pdc2027x_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
        unsigned int pio = adev->pio_mode - XFER_PIO_0;
        u32 ctcr0, ctcr1;

        PDPRINTK("adev->pio_mode[%X]\n", adev->pio_mode);

        /* Sanity check */
        if (pio > 4) {
                printk(KERN_ERR DRV_NAME ": Unknown pio mode [%d] ignored\n", pio);
                return;

        }

        /* Set the PIO timing registers using value table for 133MHz */
        PDPRINTK("Set pio regs... \n");

        ctcr0 = ioread32(dev_mmio(ap, adev, PDC_CTCR0));
        ctcr0 &= 0xffff0000;
        ctcr0 |= pdc2027x_pio_timing_tbl[pio].value0 |
                (pdc2027x_pio_timing_tbl[pio].value1 << 8);
        iowrite32(ctcr0, dev_mmio(ap, adev, PDC_CTCR0));

        ctcr1 = ioread32(dev_mmio(ap, adev, PDC_CTCR1));
        ctcr1 &= 0x00ffffff;
        ctcr1 |= (pdc2027x_pio_timing_tbl[pio].value2 << 24);
        iowrite32(ctcr1, dev_mmio(ap, adev, PDC_CTCR1));

        PDPRINTK("Set pio regs done\n");

        PDPRINTK("Set to pio mode[%u] \n", pio);
}

/**
 *      pdc2027x_set_dmamode - Initialize host controller PATA UDMA timings
 *      @ap: Port to configure
 *      @adev: um
 *      @udma: udma mode, XFER_UDMA_0 to XFER_UDMA_6
 *
 *      Set UDMA mode for device.
 *
 *      LOCKING:
 *      None (inherited from caller).
 */
static void pdc2027x_set_dmamode(struct ata_port *ap, struct ata_device *adev)
{
        unsigned int dma_mode = adev->dma_mode;
        u32 ctcr0, ctcr1;

        if ((dma_mode >= XFER_UDMA_0) &&
           (dma_mode <= XFER_UDMA_6)) {
                /* Set the UDMA timing registers with value table for 133MHz */
                unsigned int udma_mode = dma_mode & 0x07;

                if (dma_mode == XFER_UDMA_2) {
                        /*
                         * Turn off tHOLD.
                         * If tHOLD is '1', the hardware will add half clock for data hold time.
                         * This code segment seems to be no effect. tHOLD will be overwritten below.
                         */
                        ctcr1 = ioread32(dev_mmio(ap, adev, PDC_CTCR1));
                        iowrite32(ctcr1 & ~(1 << 7), dev_mmio(ap, adev, PDC_CTCR1));
                }

                PDPRINTK("Set udma regs... \n");

                ctcr1 = ioread32(dev_mmio(ap, adev, PDC_CTCR1));
                ctcr1 &= 0xff000000;
                ctcr1 |= pdc2027x_udma_timing_tbl[udma_mode].value0 |
                        (pdc2027x_udma_timing_tbl[udma_mode].value1 << 8) |
                        (pdc2027x_udma_timing_tbl[udma_mode].value2 << 16);
                iowrite32(ctcr1, dev_mmio(ap, adev, PDC_CTCR1));

                PDPRINTK("Set udma regs done\n");

                PDPRINTK("Set to udma mode[%u] \n", udma_mode);

        } else  if ((dma_mode >= XFER_MW_DMA_0) &&
                   (dma_mode <= XFER_MW_DMA_2)) {
                /* Set the MDMA timing registers with value table for 133MHz */
                unsigned int mdma_mode = dma_mode & 0x07;

                PDPRINTK("Set mdma regs... \n");
                ctcr0 = ioread32(dev_mmio(ap, adev, PDC_CTCR0));

                ctcr0 &= 0x0000ffff;
                ctcr0 |= (pdc2027x_mdma_timing_tbl[mdma_mode].value0 << 16) |
                        (pdc2027x_mdma_timing_tbl[mdma_mode].value1 << 24);

                iowrite32(ctcr0, dev_mmio(ap, adev, PDC_CTCR0));
                PDPRINTK("Set mdma regs done\n");

                PDPRINTK("Set to mdma mode[%u] \n", mdma_mode);
        } else {
                printk(KERN_ERR DRV_NAME ": Unknown dma mode [%u] ignored\n", dma_mode);
        }
}

/**
 *      pdc2027x_set_mode - Set the timing registers back to correct values.
 *      @link: link to configure
 *      @r_failed: Returned device for failure
 *
 *      The pdc2027x hardware will look at "SET FEATURES" and change the timing registers
 *      automatically. The values set by the hardware might be incorrect, under 133Mhz PLL.
 *      This function overwrites the possibly incorrect values set by the hardware to be correct.
 */
static int pdc2027x_set_mode(struct ata_link *link, struct ata_device **r_failed)
{
        struct ata_port *ap = link->ap;
        struct ata_device *dev;
        int rc;

        rc = ata_do_set_mode(link, r_failed);
        if (rc < 0)
                return rc;

        ata_link_for_each_dev(dev, link) {
                if (ata_dev_enabled(dev)) {

                        pdc2027x_set_piomode(ap, dev);

                        /*
                         * Enable prefetch if the device support PIO only.
                         */
                        if (dev->xfer_shift == ATA_SHIFT_PIO) {
                                u32 ctcr1 = ioread32(dev_mmio(ap, dev, PDC_CTCR1));
                                ctcr1 |= (1 << 25);
                                iowrite32(ctcr1, dev_mmio(ap, dev, PDC_CTCR1));

                                PDPRINTK("Turn on prefetch\n");
                        } else {
                                pdc2027x_set_dmamode(ap, dev);
                        }
                }
        }
        return 0;
}

/**
 *      pdc2027x_check_atapi_dma - Check whether ATAPI DMA can be supported for this command
 *      @qc: Metadata associated with taskfile to check
 *
 *      LOCKING:
 *      None (inherited from caller).
 *
 *      RETURNS: 0 when ATAPI DMA can be used
 *               1 otherwise
 */
static int pdc2027x_check_atapi_dma(struct ata_queued_cmd *qc)
{
        struct scsi_cmnd *cmd = qc->scsicmd;
        u8 *scsicmd = cmd->cmnd;
        int rc = 1; /* atapi dma off by default */

        /*
         * This workaround is from Promise's GPL driver.
         * If ATAPI DMA is used for commands not in the
         * following white list, say MODE_SENSE and REQUEST_SENSE,
         * pdc2027x might hit the irq lost problem.
         */
        switch (scsicmd[0]) {
        case READ_10:
        case WRITE_10:
        case READ_12:
        case WRITE_12:
        case READ_6:
        case WRITE_6:
        case 0xad: /* READ_DVD_STRUCTURE */
        case 0xbe: /* READ_CD */
                /* ATAPI DMA is ok */
                rc = 0;
                break;
        default:
                ;
        }

        return rc;
}

/**
 * pdc_read_counter - Read the ctr counter
 * @host: target ATA host
 */

static long pdc_read_counter(struct ata_host *host)
{
        void __iomem *mmio_base = host->iomap[PDC_MMIO_BAR];
        long counter;
        int retry = 1;
        u32 bccrl, bccrh, bccrlv, bccrhv;

retry:
        bccrl = ioread32(mmio_base + PDC_BYTE_COUNT) & 0x7fff;
        bccrh = ioread32(mmio_base + PDC_BYTE_COUNT + 0x100) & 0x7fff;

        /* Read the counter values again for verification */
        bccrlv = ioread32(mmio_base + PDC_BYTE_COUNT) & 0x7fff;
        bccrhv = ioread32(mmio_base + PDC_BYTE_COUNT + 0x100) & 0x7fff;

        counter = (bccrh << 15) | bccrl;

        PDPRINTK("bccrh [%X] bccrl [%X]\n", bccrh,  bccrl);
        PDPRINTK("bccrhv[%X] bccrlv[%X]\n", bccrhv, bccrlv);

        /*
         * The 30-bit decreasing counter are read by 2 pieces.
         * Incorrect value may be read when both bccrh and bccrl are changing.
         * Ex. When 7900 decrease to 78FF, wrong value 7800 might be read.
         */
        if (retry && !(bccrh == bccrhv && bccrl >= bccrlv)) {
                retry--;
                PDPRINTK("rereading counter\n");
                goto retry;
        }

        return counter;
}

/**
 * adjust_pll - Adjust the PLL input clock in Hz.
 *
 * @pdc_controller: controller specific information
 * @host: target ATA host
 * @pll_clock: The input of PLL in HZ
 */
static void pdc_adjust_pll(struct ata_host *host, long pll_clock, unsigned int board_idx)
{
        void __iomem *mmio_base = host->iomap[PDC_MMIO_BAR];
        u16 pll_ctl;
        long pll_clock_khz = pll_clock / 1000;
        long pout_required = board_idx? PDC_133_MHZ:PDC_100_MHZ;
        long ratio = pout_required / pll_clock_khz;
        int F, R;

        /* Sanity check */
        if (unlikely(pll_clock_khz < 5000L || pll_clock_khz > 70000L)) {
                printk(KERN_ERR DRV_NAME ": Invalid PLL input clock %ldkHz, give up!\n", pll_clock_khz);
                return;
        }

#ifdef PDC_DEBUG
        PDPRINTK("pout_required is %ld\n", pout_required);

        /* Show the current clock value of PLL control register
         * (maybe already configured by the firmware)
         */
        pll_ctl = ioread16(mmio_base + PDC_PLL_CTL);

        PDPRINTK("pll_ctl[%X]\n", pll_ctl);
#endif

        /*
         * Calculate the ratio of F, R and OD
         * POUT = (F + 2) / (( R + 2) * NO)
         */
        if (ratio < 8600L) { /* 8.6x */
                /* Using NO = 0x01, R = 0x0D */
                R = 0x0d;
        } else if (ratio < 12900L) { /* 12.9x */
                /* Using NO = 0x01, R = 0x08 */
                R = 0x08;
        } else if (ratio < 16100L) { /* 16.1x */
                /* Using NO = 0x01, R = 0x06 */
                R = 0x06;
        } else if (ratio < 64000L) { /* 64x */
                R = 0x00;
        } else {
                /* Invalid ratio */
                printk(KERN_ERR DRV_NAME ": Invalid ratio %ld, give up!\n", ratio);
                return;
        }

        F = (ratio * (R+2)) / 1000 - 2;

        if (unlikely(F < 0 || F > 127)) {
                /* Invalid F */
                printk(KERN_ERR DRV_NAME ": F[%d] invalid!\n", F);
                return;
        }

        PDPRINTK("F[%d] R[%d] ratio*1000[%ld]\n", F, R, ratio);

        pll_ctl = (R << 8) | F;

        PDPRINTK("Writing pll_ctl[%X]\n", pll_ctl);

        iowrite16(pll_ctl, mmio_base + PDC_PLL_CTL);
        ioread16(mmio_base + PDC_PLL_CTL); /* flush */

        /* Wait the PLL circuit to be stable */
        mdelay(30);

#ifdef PDC_DEBUG
        /*
         *  Show the current clock value of PLL control register
         * (maybe configured by the firmware)
         */
        pll_ctl = ioread16(mmio_base + PDC_PLL_CTL);

        PDPRINTK("pll_ctl[%X]\n", pll_ctl);
#endif

        return;
}

/**
 * detect_pll_input_clock - Detect the PLL input clock in Hz.
 * @host: target ATA host
 * Ex. 16949000 on 33MHz PCI bus for pdc20275.
 *     Half of the PCI clock.
 */
static long pdc_detect_pll_input_clock(struct ata_host *host)
{
        void __iomem *mmio_base = host->iomap[PDC_MMIO_BAR];
        u32 scr;
        long start_count, end_count;
        struct timeval start_time, end_time;
        long pll_clock, usec_elapsed;

        /* Start the test mode */
        scr = ioread32(mmio_base + PDC_SYS_CTL);
        PDPRINTK("scr[%X]\n", scr);
        iowrite32(scr | (0x01 << 14), mmio_base + PDC_SYS_CTL);
        ioread32(mmio_base + PDC_SYS_CTL); /* flush */

        /* Read current counter value */
        start_count = pdc_read_counter(host);
        do_gettimeofday(&start_time);

        /* Let the counter run for 100 ms. */
        mdelay(100);

        /* Read the counter values again */
        end_count = pdc_read_counter(host);
        do_gettimeofday(&end_time);

        /* Stop the test mode */
        scr = ioread32(mmio_base + PDC_SYS_CTL);
        PDPRINTK("scr[%X]\n", scr);
        iowrite32(scr & ~(0x01 << 14), mmio_base + PDC_SYS_CTL);
        ioread32(mmio_base + PDC_SYS_CTL); /* flush */

        /* calculate the input clock in Hz */
        usec_elapsed = (end_time.tv_sec - start_time.tv_sec) * 1000000 +
                (end_time.tv_usec - start_time.tv_usec);

        pll_clock = ((start_count - end_count) & 0x3fffffff) / 100 *
                (100000000 / usec_elapsed);

        PDPRINTK("start[%ld] end[%ld] \n", start_count, end_count);
        PDPRINTK("PLL input clock[%ld]Hz\n", pll_clock);

        return pll_clock;
}

/**
 * pdc_hardware_init - Initialize the hardware.
 * @host: target ATA host
 * @board_idx: board identifier
 */
static int pdc_hardware_init(struct ata_host *host, unsigned int board_idx)
{
        long pll_clock;

        /*
         * Detect PLL input clock rate.
         * On some system, where PCI bus is running at non-standard clock rate.
         * Ex. 25MHz or 40MHz, we have to adjust the cycle_time.
         * The pdc20275 controller employs PLL circuit to help correct timing registers setting.
         */
        pll_clock = pdc_detect_pll_input_clock(host);

        dev_printk(KERN_INFO, host->dev, "PLL input clock %ld kHz\n", pll_clock/1000);

        /* Adjust PLL control register */
        pdc_adjust_pll(host, pll_clock, board_idx);

        return 0;
}

/**
 * pdc_ata_setup_port - setup the mmio address
 * @port: ata ioports to setup
 * @base: base address
 */
static void pdc_ata_setup_port(struct ata_ioports *port, void __iomem *base)
{
        port->cmd_addr          =
        port->data_addr         = base;
        port->feature_addr      =
        port->error_addr        = base + 0x05;
        port->nsect_addr        = base + 0x0a;
        port->lbal_addr         = base + 0x0f;
        port->lbam_addr         = base + 0x10;
        port->lbah_addr         = base + 0x15;
        port->device_addr       = base + 0x1a;
        port->command_addr      =
        port->status_addr       = base + 0x1f;
        port->altstatus_addr    =
        port->ctl_addr          = base + 0x81a;
}

/**
 * pdc2027x_init_one - PCI probe function
 * Called when an instance of PCI adapter is inserted.
 * This function checks whether the hardware is supported,
 * initialize hardware and register an instance of ata_host to
 * libata.  (implements struct pci_driver.probe() )
 *
 * @pdev: instance of pci_dev found
 * @ent:  matching entry in the id_tbl[]
 */
static int __devinit pdc2027x_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
{
        static int printed_version;
        static const unsigned long cmd_offset[] = { 0x17c0, 0x15c0 };
        static const unsigned long bmdma_offset[] = { 0x1000, 0x1008 };
        unsigned int board_idx = (unsigned int) ent->driver_data;
        const struct ata_port_info *ppi[] =
                { &pdc2027x_port_info[board_idx], NULL };
        struct ata_host *host;
        void __iomem *mmio_base;
        int i, rc;

        if (!printed_version++)
                dev_printk(KERN_DEBUG, &pdev->dev, "version " DRV_VERSION "\n");

        /* alloc host */
        host = ata_host_alloc_pinfo(&pdev->dev, ppi, 2);
        if (!host)
                return -ENOMEM;

        /* acquire resources and fill host */
        rc = pcim_enable_device(pdev);
        if (rc)
                return rc;

        rc = pcim_iomap_regions(pdev, 1 << PDC_MMIO_BAR, DRV_NAME);
        if (rc)
                return rc;
        host->iomap = pcim_iomap_table(pdev);

        rc = pci_set_dma_mask(pdev, ATA_DMA_MASK);
        if (rc)
                return rc;

        rc = pci_set_consistent_dma_mask(pdev, ATA_DMA_MASK);
        if (rc)
                return rc;

        mmio_base = host->iomap[PDC_MMIO_BAR];

        for (i = 0; i < 2; i++) {
                struct ata_port *ap = host->ports[i];

                pdc_ata_setup_port(&ap->ioaddr, mmio_base + cmd_offset[i]);
                ap->ioaddr.bmdma_addr = mmio_base + bmdma_offset[i];

                ata_port_pbar_desc(ap, PDC_MMIO_BAR, -1, "mmio");
                ata_port_pbar_desc(ap, PDC_MMIO_BAR, cmd_offset[i], "cmd");
        }

        //pci_enable_intx(pdev);

        /* initialize adapter */
        if (pdc_hardware_init(host, board_idx) != 0)
                return -EIO;

        pci_set_master(pdev);
        return ata_host_activate(host, pdev->irq, ata_interrupt, IRQF_SHARED,
                                 &pdc2027x_sht);
}

/**
 * pdc2027x_init - Called after this module is loaded into the kernel.
 */
static int __init pdc2027x_init(void)
{
        return pci_register_driver(&pdc2027x_pci_driver);
}

/**
 * pdc2027x_exit - Called before this module unloaded from the kernel
 */
static void __exit pdc2027x_exit(void)
{
        pci_unregister_driver(&pdc2027x_pci_driver);
}

module_init(pdc2027x_init);
module_exit(pdc2027x_exit);